Medical drill

ABSTRACT

A medical drill is disclosed, which is made of amorphous alloy, the amorphous alloy is a Ti-based amorphous alloy which comprises titanium in 40 at % or above, wherein the tensile strength of the medical drill is 1600-2600 MPa, and the Vicker&#39;s hardness of the medical drill is 600-800.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 13/430,310, filed on Mar. 26, 2012, which claims the benefitsof the Taiwan Patent Application Serial Number 100113363, filed on Apr.18, 2011. This application also claims the benefits of the Taiwan PatentApplication Serial Number 100113363, filed on Apr. 18, 2011, the subjectmatter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical drill, more particularly, toa medical drill made of an amorphous alloy.

2. Description of Related Art

Generally, during medical surgery related to bone repair, such as hip orknee replacement for treating broken bones, dental implants, anddebridement, bone drilling is often necessary for implanting bonescrews. For example, in treating a broken bone, a drill can be used toperform a bone drilling process and a bone screw is screwed into thebone to fix the broken bone. During the bone drilling surgery, a medicaldrill is necessary.

Medical drills are widely used in orthopedic or dental treatment. Ingeneral fracture surgery, a space with a certain size and depth would beformed in the bone by a medical drill, and then the location of the bonewould be fixed through bone implants, such as bone screws and boneplates. In the dental field, dental drills are used in orthodontictreatment or dental implant treatment to form an opening on a gum andthen to fix a bracket or a dental implant.

However, the drills used in the orthopedic and dental fields aregenerally made of martensitic stainless steel with a crystallinestructure and an elastic limit less than 0.5%, and thereby the shift ofthe normal vector of force away from the center axis often causes thebreaking of drills, resulting in surgical inconvenience and even medicaldisputes.

Regarding medical drills, US 2009208902 discloses a dental drill made ofplastics. Also, U.S. Pat. No. 6,312,432 suggests a bone drill, but failsto disclose a novel material for medical drills.

As shown in FIG. 1, a medical drill generally has a pillar body, andthreads 11 are formed in a certain portion of the pillar body. However,a conventional medical drill is often made of a crystalline metal, suchas stainless steel (e.g. martensitic stainless steel), an alloy,ceramic, or plastic material. Therefore, breaking of medical drillsoften occurs and causes surgical inconvenience.

Hence, it is desirable to develop for medical drills a novel materialwhich has excellent properties of good fracture resistance, enhancedcorrosion resistance, high wear resistance, improved toughness and highhardness, and is advantageous to the operation of orthopedic or dentaltreatment.

SUMMARY OF THE INVENTION

The present invention provides a medical drill made of an amorphousalloy, in which the amorphous alloy is a Zr-based amorphous alloy whichcontains zirconium metal in 45 at % or more, and the medical drill has atensile strength of 1500-2500 MPa and a Vickers hardness of 400-750.

The medical drill according to the present invention can be used as abone drill or a dental drill. Through tests under practical operation,it can be confirmed that the medical drill made of the amorphous alloyaccording to the present invention has excellent properties of goodfracture resistance, enhanced corrosion resistance, high wearresistance, improved toughness and high hardness compared toconventional medical drills made of crystalline alloys. That is, theconventional art cannot achieve the above-mentioned excellentproperties.

In the present invention, the amorphous alloys can be applied in medicalbone drills and exhibit better properties compared to the alloymaterials used in conventional drills. The drill made of the amorphousmaterial according to the present invention has excellent propertiesequal to surgical knifes, such as good toughness, high hardness andenhanced fracture resistance, and thus can meet the requirements formedical use.

The amorphous alloys of the present invention include Zr-based amorphousalloys and have higher glass transition temperature and activationenergy. In addition, silicon, boron, yttrium, palladium or tantalum maybe added into the amorphous alloys to enhance the thermal stability andmechanical properties of the amorphous alloys (or to inhibitcrystallized nucleation of supercooled metallic liquid).

So far, little research focuses on the application of amorphousmaterials in clinical medicine. The Zr-based or Ti-based amorphousalloys have great potential for the application in, for example, medicaldevices, bio-medical implants and medical materials, owing to theexcellent properties of amorphous alloys, such as corrosion resistance,wear resistance and so on, and their related research presents greatpromise in both scientific and practical applications.

The medical drill according to the present invention can be shaped in apillar body by a turning process, and a spiral structure can be formedin a portion of the pillar body. The medical drill according to thepresent invention may be manufactured by preparing an amorphous alloyrod through rapid cooling, forming a spiral structure in a portion ofthe amorphous alloy rod by heating (not higher than crystallizationtemperature (Tx)) and then a stretching and twisting process, andfinally cooling it to obtain the medical drill according to the presentinvention.

Preferably, the medical drill according to the present invention isshaped in a pillar body, and a thread is formed in a part of the pillarbody. The medical drill according to the present invention may bemanufactured by preparing an amorphous alloy rod through rapid cooling,and forming a spiral structure in a portion of the amorphous alloy rodby a sculpturing process to thereby obtain the medical drill accordingto the present invention.

In the process for manufacturing the medical drill according to thepresent invention, the processing method of the amorphous alloy rod isnot limited to a stretching and twisting process and a sculpturingprocess, and may use other processing methods of metal materials as longas the arrangement of metal atoms in the amorphous alloy would not bedamaged in the processing way (that is, the processing temperaturecannot exceed the crystallization temperature (Tx)).

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably contains zirconium in 45 at % or more,aluminum in 5-10 at %, copper in 15-20 at % and nickel in 5-15 at %.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably further contains silicon, boron, yttrium,palladium or tantalum in 1 at % or more.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably is represented by the following formula 1,

Zr_(a)Al_(b)Cu_(c)Ni_(d)Si_(e),  [formula 1]

in which, 45=<a=<75, 5=<b=<10, 15=<c=<20, 5=<d=<15, 1=<e=<10.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably further contains Si and other elements so asto enhance the packing density of atoms in the amorphous alloy, improvethe thermal stability and mechanical properties of the amorphous alloy,and maintain longer incubation time during isothermal annealing in thesupercooled liquid region. In addition, it is confirmed that theaddition of an Si element can enhance the thermal stability of theZr-based amorphous alloy to be 2-3 times higher compared to the additionof a boron element.

According to the medical drill of the present invention, the formula 1preferably is Zr₆₁Al_(7.5)Cu_(17.5)Ni₁₀Si₄.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably is represented by the following formula 2,

Zr_(a)Al_(b)Cu_(c)Ni_(d)B_(e),  [formula 2]

in which, 45=<a=<75, 5=<b=<10, 15=<c=<20, 5=<d=<15, 1=<e=<10.

According to the medical drill of the present invention, the formula 2preferably is Zr₆₁Al_(7.5)Cu_(17.5)Ni₁₀B₂.

In the present invention, the Zr-based amorphous alloy preferablyfurther contains boron and other elements in addition to Zr metal so asto improve the thermal stability of the Zr-based amorphous alloy and tomaintain longer incubation time during isothermal annealing in thesupercooled liquid region.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably is represented by the following formula 3,

Zr_(a)Al_(b)Cu_(c)Ni_(d)B_(e),  [formula 3]

in which, 45=<a=<75, 5=<b=<10, 15=<c=<30, 5=<d=<15, 1=<e=<15.

According to the medical drill of the present invention, the formula 3preferably is Zr₅₃Cu_(30-x)Ni₉Al₈Ta_(x), in which 0.1=<x=<10.

In the present invention, the Zr-based amorphous alloy further containstantalum and other elements in addition to Zr metal. Through tests, itcan be confirmed that the addition of tantalum can increase plasticdeformation of the amorphous alloy rod and thus makes the subsequentprocess more convenient to be performed.

According to the medical drill of the present invention, the Zr-basedamorphous alloy preferably is represented by the following formula 4,

Zr_(a)Al_(b)Cu_(c)Pd_(d)Nb_(e),  [formula 4]

in which, 45=<a=<75, 5=<b=<10, 15=<c=<30, 0=<d=<9, 0=<e=<9.

According to the medical drill of the present invention, the formula 4preferably is Zr₅₃Al₈Cu₃₀Pd_(x)Nb_(y), in which x=4.5, y=4.5. Thenickel-free Zr-based amorphous alloy can have higher ductility andtoughness.

The present invention further provides a medical drill made of anamorphous alloy, in which the amorphous alloy is a Ti-based amorphousalloy which contains titanium in 40 at % or more, and the Ti-basedamorphous alloy has a tensile strength (maximum tensile strength) of1600-2600 MPa and a Vickers hardness of 600-800. For example, theTi-based amorphous alloy can be 2148 MPa in tensile strength (maximumtensile strength) and 709 in Vickers hardness.

The medical drill of the present invention may be used as a bone drillor a dental drill. Through tests under practical operation, it can beconfirmed that the medical drill made of the amorphous alloy accordingto the present invention has excellent properties of good fractureresistance, enhanced corrosion resistance, high wear resistance,improved toughness and high hardness compared to conventional medicaldrills made of crystalline alloys. That is, the conventional art cannotachieve the above-mentioned excellent properties. In addition, theTi-based amorphous alloy has reduced weight due to titanium beinglighter in weight, and has an elastic limit of 6% or more.

In the present invention, the amorphous alloys are applied in medicalbone drills and exhibit better properties compared to the alloymaterials used in conventional drills. The drill made of the amorphousmaterial according to the present invention has excellent propertiesequal to surgical knifes, such as good toughness, high hardness andenhanced fracture resistance, and thus can meet the requirements formedical use.

The amorphous alloys of the present invention include Ti-based amorphousalloys and have higher glass transition temperature and activationenergy. In addition, silicon, boron, yttrium, palladium or tantalum maybe added into the Ti-based amorphous alloys to enhance the thermalstability and mechanical properties of the amorphous alloys (or toinhibit crystallized nucleation of supercooled metallic liquid).

So far, little research focuses on the application of amorphousmaterials in clinical medicine. The Zr-based or Ti-based amorphousalloys have great potential for the application in, for example, medicaldevices, bio-medical implants and medical materials, owing to theexcellent properties of amorphous alloys, such as corrosion resistance,wear resistance and so on, and their related research presents greatpromise in both scientific and practical applications.

The medical drill according to the present invention can be shaped in apillar body, and a spiral structure can be formed in a portion of thepillar body. The medical drill according to the present invention may bemanufactured by preparing an amorphous alloy rod through rapid cooling,forming a spiral structure in a portion of the amorphous alloy rod byheating (not higher than crystallization temperature (Tx)) and then astretching and twisting process, and finally cooling it to obtain themedical drill according to the present invention.

Preferably, the medical drill according to the present invention isshaped in a pillar body, and a thread is formed in a part of the pillarbody. The medical drill according to the present invention may bemanufactured by preparing an amorphous alloy rod through rapid cooling,and forming a spiral structure in a portion of the amorphous alloy rodby a sculpturing process to thereby obtain the medical drill accordingto the present invention.

The process for manufacturing the medical drill according to the presentinvention, the processing method of the amorphous alloy rod is notlimited to a stretching and twisting process and a sculpturing process,and may use other processing methods of metal materials as long as thearrangement of metal atoms in the amorphous alloy would not be damagedin the processing way (that is, the processing temperature cannot exceedthe crystallization temperature (Tx)).

According to the medical drill of the present invention, the Ti-basedamorphous alloy preferably contains titanium in 40 at % or more, copperin 30-40 at %, palladium in 10-20 at % and zirconium in 5-15 at %.

According to the medical drill of the present invention, the Ti-basedamorphous alloy preferably further contains Si in 1 wt % or more. In themedical drill of the present invention, silicon and other elementspreferably can be added therein so as to enhance the packing density ofatoms in the amorphous alloy, improve the thermal stability andmechanical properties of the amorphous alloy, and maintain longerincubation time during isothermal annealing in the supercooled liquidregion. In addition, it is confirmed that the addition of an Si elementcan enhance the thermal stability of the Ti-based amorphous alloy to be2-3 times higher compared to the addition of boron element.

According to the medical drill of the present invention, the Ti-basedamorphous alloy preferably is represented by the following formula 5,

Ti_(a)Cu_(b)Pd_(c)Zr_(d)Si_(e),  [formula 5]

in which, 40=<a=<75, 30=<b=<40, 10=<c=<20, 5=<d=<15, 0.05=<e=<2.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a conventional medical drill;

FIG. 2 is a schematic diagram of a medical drill according to Example 1of the present invention; and

FIG. 3 is a schematic diagram of a medical drill according to Example 7of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereafter, examples will be provided to illustrate the embodiments ofthe present invention. Those skilled in the art can easily understandthe advantages and effects of the invention from the disclosure of thepresent invention. The following examples are intended for illustratingthe embodiments of the subject invention, but not for excluding otherembodiments. Those skilled in the art can omit, modify, reduce or varycomponents without departing from the spirit of the invention.

Example 1 Medical Drill of Zr-Based Amorphous Alloy

An amorphous alloy rod (8 mmφ×70 mm L) is manufactured by usingZr₆₁Al_(7.5)Cu_(17.5)Ni₁₀Si₄ as the material and performing suctioncasting and rapid cooling.

Subsequently, the amorphous alloy rod is processed at normaltemperature, and a stretching and twisting process is performed in alow-temperature water recycling system which can ensure the worktemperature is not higher than the crystallization temperature (Tx) toform a spiral structure in a certain portion of the amorphous alloy rodand thereby to obtain the medical drill of the present example, as shownin FIG. 2.

As shown in FIG. 2, the medical drill 2 according to the present examplehas a pillar body of which a certain portion 21 is structured in aspiral shape. Additionally, the medical drill 2 according to the presentexample is made of Zr-based amorphous alloy containing 45% or more of Zrmetal.

In the present example, the Zr-based amorphous alloy further contains Siand other elements in addition to Zr metal so as to enhance the packingdensity of atoms in the amorphous alloy, improve the thermal stabilityand mechanical properties of the amorphous alloy, and maintain longerincubation time during isothermal annealing in the supercooled liquidregion. In addition, it is confirmed that the addition of an Si elementcan enhance the thermal stability of the Zr-based amorphous alloy to be2-3 times higher compared to the addition of a boron element.

The tensile strength, Vickers hardness and specific gravity of themedical drill made of the Zr-based amorphous alloy according to thepresent example is measured as 1600-1800 MPa, 550-650 and 5.9-6.7 kg/L,respectively. The above-mentioned excellent properties cannot be foundin general crystalline metal.

The medical drill according to the present example can be used as a bonedrill or a dental drill. Through tests under practical operation, it canbe confirmed that the medical drill made of the amorphous alloyaccording to the present example has excellent properties of goodfracture resistance, enhanced corrosion resistance, high wearresistance, improved toughness and high hardness compared toconventional medical drills made of crystalline alloys. That is, theconventional art cannot achieve the above-mentioned excellentproperties.

Example 2 Medical Drill of Zr-Based Amorphous Alloy

An amorphous alloy rod (10 mmφ×60 mm L) is manufactured by usingZr₆₁Al_(7.5)Cu_(17.5)Ni₁₀B₂ as the material and performing suctioncasting and rapid cooling.

Subsequently, the amorphous alloy rod is processed at normaltemperature, and a stretching and twisting process is performed in alow-temperature water recycling system which can ensure the worktemperature is not higher than the crystallization temperature (Tx) toform a spiral structure in a certain portion of the amorphous alloy rodand thereby to obtain the medical drill of the present example.

In the present example, the Zr-based amorphous alloy further containsboron and other elements in addition to Zr metal so as to improve thethermal stability and mechanical properties of the Zr-based amorphousalloy, and maintain longer incubation time during isothermal annealingin the supercooled liquid region.

Example 3 Medical Drill of Zr-Based Amorphous Alloy

The medical drill made of Zr-based amorphous alloy according to thepresent example is manufactured by the same process as that illustratedin Example 1, except that the present example usesZr₅₃Cu_(30-x)Ni₉Al₈Ta_(x) as material and the size of the amorphousalloy rod prepared in the present example is 2 mmφ×30 mm L.

In the present example, the Zr-based amorphous alloy further containstantalum and other elements in addition to Zr metal. Through tests, itcan be confirmed that the addition of tantalum can increase plasticdeformation of the amorphous alloy rod and thus makes the subsequentprocess more convenient to be performed.

Example 4 Medical Drill of Zr-Based Amorphous Alloy

The medical drill made of Zr-based amorphous alloy according to thepresent example is manufactured by the same process as that illustratedin Example 1, except that the present example usesZr_(63.8)Ni_(16.2)Cu₁₅Al₅ as material.

In the present example, the Zr-based amorphous alloy contains Zr metalas a major component and nickel, copper and aluminum, but does notcontain metalloid elements, i.e. silicon and boron.

Example 5 Medical Drill of Zr-Based Amorphous Alloy

The medical drill made of Zr-based amorphous alloy according to thepresent example is manufactured by the same process as that illustratedin Example 1, except that the present example usesZr₅₃Al₈Cu₃₀Pd_(x)Nb_(y) (x=4.5, y=4.5) as material.

In the present example, the medical drill is made of nickel-freeZr-based amorphous alloy and has higher ductility and toughness.

Example 6 Medical Drill of Ti-Based Amorphous Alloy

An amorphous alloy rod (5 mmφ×50 mm L) is manufactured by usingTi_(a)Cu_(b)Pd_(c)Zr_(d)Si_(e) (40=<a=<75, 30=<b=<40, 10=<c=<20,0.05=<e=<2) as the material and performing suction casting and rapidcooling.

Subsequently, the amorphous alloy rod is processed at normaltemperature, and a stretching and twisting process is performed in alow-temperature water recycling system which can ensure the worktemperature is not higher than the crystallization temperature (Tx) toform a spiral structure in a certain portion of the amorphous alloy rodand thereby to obtain the medical drill of the present example.Regarding the medical drill made of the Ti-based amorphous alloyaccording to the present example, the Ti-based amorphous alloy ismeasured as 2148 MPa in tensile strength (maximum tensile strength) and709 in Vickers hardness.

The medical drill according to the present example has reduced weightdue to titanium weighing less weight, and has an elastic limit of 6% ormore.

Example 7 Medical Drill of Zr-Based Amorphous Alloy

An amorphous alloy rod (10 mmφ×60 mm L) is manufactured by usingZr₆₁Al_(7.5)Cu_(17.5)Ni₁₀B₂ as the material and performing suctioncasting and rapid cooling.

Subsequently, the amorphous alloy rod is processed by a sculpturingprocess to form threads in a certain portion of the amorphous alloy rodand thereby to obtain the medical drill of the present example, as shownin FIG. 3.

As shown in FIG. 3, the medical drill 3 according to the present examplehas a pillar body, and threads 32 are formed in a certain portion 31 ofthe pillar body. Additionally, the medical drill 3 according to thepresent example is made of Zr-based amorphous alloy containing 45 at %or more of Zr metal.

In the present example, the amorphous alloy rod is processed by asculpturing process rather than a stretching and twisting process. Inthe present invention, the amorphous alloy rod may be processed in otherprocessing ways in addition to a stretching and twisting process and asculpturing process, as long as the arrangement of metal atoms in theamorphous alloy would not be damaged in the processing way (that is, theprocessing temperature cannot exceed the crystallization temperature(Tx)).

In the present invention, the amorphous alloys are applied in medicalbone drills and exhibit better properties compared to the alloymaterials used in conventional drills. The drill made of the amorphousmaterial according to the present invention has excellent propertiesequal to surgical knifes, such as good toughness, high hardness andenhanced fracture resistance, and thus can meet the requirements formedical use.

The amorphous alloys of the present invention include Zr-based amorphousalloys and Ti-based amorphous alloys and have higher glass transitiontemperature and activation energy. In addition, silicon, boron, yttrium,palladium or tantalum may be added into the amorphous alloys to enhancethe thermal stability and mechanical properties of the amorphous alloys(or to inhibit crystallized nucleation of supercooled metallic liquid).

So far, little research focuses on the application of amorphousmaterials in clinical medicine. The Zr-based or Ti-based amorphousalloys have great potential for the application in, for example, medicaldevices, bio-medical implants and medical materials, owing to theexcellent properties of amorphous alloys, such as corrosion resistance,wear resistance and so on, and their related research presents greatpromise in both scientific and practical applications.

The above examples are intended for illustrating the embodiments of thesubject invention and the technical features thereof, but not forrestricting the scope of protection of the subject invention. The scopeof the subject invention is based on the claims as appended.

What is claimed is:
 1. A medical drill made of an amorphous alloy,wherein the amorphous alloy is a Ti-based amorphous alloy whichcomprises titanium in 40 at % or more, and the Ti-based amorphous alloyhas a tensile strength of 1600-2600 MPa and a Vickers hardness of600-800.
 2. The medical drill as claimed in claim 1, wherein the medicaldrill is shaped in a pillar body, and a spiral structure is formed in aportion of the pillar body.
 3. The medical drill as claimed in claim 1,wherein the medical drill is shaped in a pillar body, and a thread isformed in a portion of the pillar body.
 4. The medical drill as claimedin claim 1, wherein the Ti-based amorphous alloy comprises titanium in40 at % or more, copper in 30-40 at %, palladium in 10-20 at % andzirconium in 5-15 at %.
 5. The medical drill as claimed in claim 1,wherein the Ti-based amorphous alloy further comprises silicon in 1 wt %or more.
 6. The medical drill as claimed in claim 1, wherein theTi-based amorphous alloy is represented by the following formula 5,Ti_(a)Cu_(b)Pd_(c)Zr_(d)Si_(e),  [formula 5] wherein 40=<a=<75,30=<b=<40, 10=<c=<20, 5=<d=<15, 0.05=<e=<2.